6,773 research outputs found
Ultra-Reliable Low Latency Communication (URLLC) using Interface Diversity
An important ingredient of the future 5G systems will be Ultra-Reliable
Low-Latency Communication (URLLC). A way to offer URLLC without intervention in
the baseband/PHY layer design is to use interface diversity and integrate
multiple communication interfaces, each interface based on a different
technology. In this work, we propose to use coding to seamlessly distribute
coded payload and redundancy data across multiple available communication
interfaces. We formulate an optimization problem to find the payload allocation
weights that maximize the reliability at specific target latency values. In
order to estimate the performance in terms of latency and reliability of such
an integrated communication system, we propose an analysis framework that
combines traditional reliability models with technology-specific latency
probability distributions. Our model is capable to account for failure
correlation among interfaces/technologies. By considering different scenarios,
we find that optimized strategies can in some cases significantly outperform
strategies based on -out-of- erasure codes, where the latter do not
account for the characteristics of the different interfaces. The model has been
validated through simulation and is supported by experimental results.Comment: Accepted for IEEE Transactions on Communication
Reliable and Low-Latency Fronthaul for Tactile Internet Applications
With the emergence of Cloud-RAN as one of the dominant architectural
solutions for next-generation mobile networks, the reliability and latency on
the fronthaul (FH) segment become critical performance metrics for applications
such as the Tactile Internet. Ensuring FH performance is further complicated by
the switch from point-to-point dedicated FH links to packet-based multi-hop FH
networks. This change is largely justified by the fact that packet-based
fronthauling allows the deployment of FH networks on the existing Ethernet
infrastructure. This paper proposes to improve reliability and latency of
packet-based fronthauling by means of multi-path diversity and erasure coding
of the MAC frames transported by the FH network. Under a probabilistic model
that assumes a single service, the average latency required to obtain reliable
FH transport and the reliability-latency trade-off are first investigated. The
analytical results are then validated and complemented by a numerical study
that accounts for the coexistence of enhanced Mobile BroadBand (eMBB) and
Ultra-Reliable Low-Latency (URLLC) services in 5G networks by comparing
orthogonal and non-orthogonal sharing of FH resources.Comment: 11pages, 13 figures, 3 bio photo
Latency Analysis of Systems with Multiple Interfaces for Ultra-Reliable M2M Communication
One of the ways to satisfy the requirements of ultra-reliable low latency
communication for mission critical Machine-type Communications (MTC)
applications is to integrate multiple communication interfaces. In order to
estimate the performance in terms of latency and reliability of such an
integrated communication system, we propose an analysis framework that combines
traditional reliability models with technology-specific latency probability
distributions. In our proposed model we demonstrate how failure correlation
between technologies can be taken into account. We show for the considered
scenario with fiber and different cellular technologies how up to 5-nines
reliability can be achieved and how packet splitting can be used to reduce
latency substantially while keeping 4-nines reliability. The model has been
validated through simulation.Comment: Accepted for IEEE SPAWC'1
Latency Bounds of Packet-Based Fronthaul for Cloud-RAN with Functionality Split
The emerging Cloud-RAN architecture within the fifth generation (5G) of
wireless networks plays a vital role in enabling higher flexibility and
granularity. On the other hand, Cloud-RAN architecture introduces an additional
link between the central, cloudified unit and the distributed radio unit,
namely fronthaul (FH). Therefore, the foreseen reliability and latency for 5G
services should also be provisioned over the FH link. In this paper, focusing
on Ethernet as FH, we present a reliable packet-based FH communication and
demonstrate the upper and lower bounds of latency that can be offered. These
bounds yield insights into the trade-off between reliability and latency, and
enable the architecture design through choice of splitting point, focusing on
high layer split between PDCP and RLC and low layer split between MAC and PHY,
under different FH bandwidth and traffic properties. Presented model is then
analyzed both numerically and through simulation, with two classes of 5G
services that are ultra reliable low latency (URLL) and enhanced mobile
broadband (eMBB).Comment: 6 pages, 7 figures, 3 tables, conference paper (ICC19
Feasibility Study of Enabling V2X Communications by LTE-Uu Radio Interface
Compared with the legacy wireless networks, the next generation of wireless
network targets at different services with divergent QoS requirements, ranging
from bandwidth consuming video service to moderate and low date rate machine
type services, and supporting as well as strict latency requirements. One
emerging new service is to exploit wireless network to improve the efficiency
of vehicular traffic and public safety. However, the stringent packet
end-to-end (E2E) latency and ultra-low transmission failure rates pose
challenging requirements on the legacy networks. In other words, the next
generation wireless network needs to support ultra-reliable low latency
communications (URLLC) involving new key performance indicators (KPIs) rather
than the conventional metric, such as cell throughput in the legacy systems. In
this paper, a feasibility study on applying today's LTE network infrastructure
and LTE-Uu air interface to provide the URLLC type of services is performed,
where the communication takes place between two traffic participants (e.g.,
vehicle-to-vehicle and vehicle-to-pedestrian). To carry out this study, an
evaluation methodology of the cellular vehicle-to-anything (V2X) communication
is proposed, where packet E2E latency and successful transmission rate are
considered as the key performance indicators (KPIs). Then, we describe the
simulation assumptions for the evaluation. Based on them, simulation results
are depicted that demonstrate the performance of the LTE network in fulfilling
new URLLC requirements. Moreover, sensitivity analysis is also conducted
regarding how to further improve system performance, in order to enable new
emerging URLLC services.Comment: Accepted by IEEE/CIC ICCC 201
Low-Latency Short-Packet Transmissions: Fixed Length or HARQ?
We study short-packet communications, subject to latency and reliability
constraints, under the premises of limited frequency diversity and no time
diversity. The question addressed is whether, and when, hybrid automatic repeat
request (HARQ) outperforms fixed-blocklength schemes with no feedback (FBL-NF)
in such a setting. We derive an achievability bound for HARQ, under the
assumption of a limited number of transmissions. The bound relies on
pilot-assisted transmission to estimate the fading channel and scaled
nearest-neighbor decoding at the receiver. We compare our achievability bound
for HARQ to stateof-the-art achievability bounds for FBL-NF communications and
show that for a given latency, reliability, number of information bits, and
number of diversity branches, HARQ may significantly outperform FBL-NF. For
example, for an average latency of 1 ms, a target error probability of 10^-3,
30 information bits, and 3 diversity branches, the gain in energy per bit is
about 4 dB.Comment: 6 pages, 5 figures, accepted to GLOBECOM 201
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